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We have this debate going on, on the F10 Boards, and am curious to see what you guys may have experienced on the matter.

We all know the N55 is underrated, presumedly due to keeping insurance costs on volume models down (as I can attest to as the insurance rate on my 535i was pleasantly surprisingly lower than my previous car) but "how much" is the question, My theorizing and calculations give me the impression we're seeing anywhere from 325-340 crank HP from them.

My reasons for drawing those conclusions:

-A brand new, non broken in 535i was video'd to dyno at 277 RWHP/283 RWTQ (with some miles over 280 will be attainable). Using a 17-20% drivetrain loss, you get over 330+HP.

-The 535i is a 4100 lb car, which has been documented by magazines to attain a Trap Speed from 99-101 MPH regularly (Trap Speed IMO is the most honest indicator of HP). Using "Drag Time Calculators", a car that weighs that much needs about 336 (Crank) HP to trap that high.

-My "real life" experiences dragging older Manual SN-99 Mustang GT's (260 crank HP, dyno's at 225 RWHP, with less drivetrain loss due to not being automatic, but obviously far less efficient than newer BMW's) showed those 3200 lbs GT's did 14.0 @ 100 MPH drag runs, which is about identical to some F10 535i "Magazine runs". Therefore using the "100 lbs = 10 HP rule", a 535i which weighs 800-900 lbs more would need 80-90 more HP to trap at the same times. Which would = around 340 crank HP (280-ish RWHP).

-And finally, I've heard people say 3-Series N55's have dyno'd at around 290 RWHP, which would mean these cars dyno at the wheels closer to their "marketed" HP numbers.